This is a prospective study of risk factors associated with intrauterine growth retardation. Recruited were pregnant women before 17 weeks gestation at the University of Alabama in Birmingham and University of Trondheim, Norway (in collaboration with the Universities of Bergen and Uppsala) for the period of January 1986 through June 1988. The children are followed for five years to monitor cognitive, physical and behavioral development. Analysis will focus on: . The intrauterine growth curve. . The impact of socioeconomic factors, psychosocial factors, behavioral risk factors, nutritional factors on intrauterine growth. . Cognitive, behavioral, psychological and nutritional status at 5 years among group with different rates of intrauterine growth, and different postnatal social and environmental factors. . Postnatal growth for growth retarded infants.